The objectives of the proposed research are to answer the following questions: 1. What are the precursors for the synthesis of alkyl and alk-1'-enyl glyceryl ethers in Clostridium butyricum? 2. What are the intermediates leading to the synthesis of alkyl and alk-1'-enyl glyceryl ethers in this organism and what are the cofactors required for their synthesis? 3. What are the characteristics of the enzymes involved in the synthesis of alkyl and alk-1'-enyl glyceryl ethers in Clostridium butyricum? 4. Where and how are controls exerted on the synthesis of alkyl and alk-1'-enyl glyceryl ethers in Clostridium butyricum? To study the synthesis of alk-1'-enyl glyceryl ethers in the anaerobic bacterium Clostridium butyricum, the following three general approaches will be pursued: 1. Incorporation studies of radioactivity from potential precursors of the alk-1'-enyl glyceryl ether molecule in growing cells. 2. Turnover of the whole or part of phospholipid molecules in intact cells of Clostridium butyricum. 3. Use of cell- free suspension prepared from logarithmically growing cultures of Clostridium butyricum for studies of phospholipid biosynthesis.